Physical fitness and conditioning have become increasingly popular in today's health conscious society. This has resulted in the development of several different types of exercise devices. One of these devices is the treadmill, which has become popular for providing an indoors workout of running, jogging or walking. Treadmills have been installed in a variety of workout environments including health clubs and homes.
It is known in the art to provide a treadmill with either a motorized or non-motorized tread or belt. Examples of previous treadmills include the devices disclosed in U.S. Pat. Nos. 4,749,181 (issued to Pittaway); 3,731,917 (issued to Townsend); and 3,711,812, issued to Cherry. Each of these patents generally discloses motorized belt treadmills having motors to drive the belts at fixed speeds. Such devices, however, have drawbacks associated with requiring the user to maintain an exact pace with the motor or else requiring the user to constantly adjust the speed of the motor. This can be frustrating, can diminish the user's perception of the quality of the workout, or can frustrate the user so that the user does not want to utilize the treadmill. Additionally, the user may feel that the workout is "jarring" if the user has a slightly different pace than the belt speed (e.g., the belt forces the user to rapidly adjust the pace as the user's feet contact the belt).
It is also known in the art to provide non-motorized treadmills. One example of a non-motorized treadmill is manufactured by NordicTrack, Inc., of Chaska, Minn. (the assignee of the present invention) under the model designation WALKFIT. Non-motorized treadmills allow users to vary their pace, avoid jerky starts and stops, and eliminate the motors and electronics for controlling the speed of the belt. However, since the user provides the power to keep the belt moving, inertial devices and/or brakes are generally required to help maintain the speed of the belt. Also, non-motorized treadmills do not allow for paced workouts and may not approximate the sense of running, jogging or walking on ground as realistically as motorized treadmills--since the user must power the belt.
Therefore, a need exists in the art for a motorized treadmill device for assisting in maintaining a treadmill belt moving at a predetermined speed, while allowing the user to exceed the predetermined speed. A need also exists for such a device which further provides for controlling the excess force imparted on the belt by the user when exceeding the predetermined speed.